Grid Reference Converter
Convert UK/Irish National Grid references to latitude/longitude coordinates.
UK National Grid (e.g., TQ 30000 80000, TQ3080, or 530000 180000)
Supported Formats
- TQ 30000 80000 (letters + full easting/northing)
- TQ 300 800 (letters + 3-digit)
- TQ3080 (letters + compressed)
- 530000 180000 (numeric only)
Common Grid Squares
What is a Grid Reference?
A grid reference is a location on a map identified by coordinates on a projected grid system. The UK and Ireland use the Ordnance Survey National Grid, which divides the country into 100km squares identified by two letters.
UK National Grid Format
Grid references use a two-letter prefix followed by numeric eastings and northings:
- TQ 30000 80000: Full 10-figure reference (1m precision)
- TQ 300 800: 6-figure reference (100m precision)
- TQ 30 80: 4-figure reference (1km precision)
Grid Squares
Common grid squares in England:
- TQ: London and Southeast
- SP: Midlands
- SE/SK: Yorkshire/East Midlands
- SJ: Northwest England
- NY: Lake District
Grid References in Geocaching
Grid references are used in UK geocaching because:
- Ordnance Survey maps: Standard UK mapping
- Local knowledge: Familiar to UK cachers
- Puzzle encoding: Different format to confuse
- Historical caches: Pre-GPS coordinate format
Converting Grid References
To convert to GPS coordinates:
- Identify the two-letter grid square
- Add the easting (E) and northing (N)
- Apply the OSGB36 to WGS84 transformation
- Result is decimal degrees lat/long
Precision
| Figures | Example | Precision |
|---|---|---|
| 4 figures | TQ 30 80 | 1 km |
| 6 figures | TQ 300 800 | 100 m |
| 8 figures | TQ 3000 8000 | 10 m |
| 10 figures | TQ 30000 80000 | 1 m |